Equipment used in abrasive environments is subject to excessive wear that can erode exposed surfaces. Exposed surfaces of equipment in mining operations where large volumes of earthen materials are extracted and processed are especially subject to wear. There are many methods for extending the service life of exposed components. Material selection for the component can provide improved wear resistance but has to be balanced with other properties and uses of the component. A hard wear layer is often applied to surfaces of a component by welding or other methods to provide a thicker and harder surface that extends the service life of the equipment. This hardfacing can be renewed as it wears away, but the application process is labor intensive and can take the equipment out of service for extended periods. The larger the equipment, the more time is required to apply the hardfacing and the longer the equipment is taken out of service.
Some equipment can be provided with replaceable liners that are installed to cover larger areas of the equipment. Liners have been used in trays of off road dump trucks that accept and dump material hauled from mines. Large dump trucks working in open mines are positioned under a bucket that excavates or gathers blasted material and drops the load, which can weigh hundreds of tons, onto the surface of the tray. The material is hauled to another location and dumped. The material includes hard particles which are held against the tray surface by the tons of material above it. When the tray is tilted back to dump the load, these particles scratch and abrade the surface of the tray. The mines often run continually day and night and the trays of the dump trucks are quickly worn. Buckets can experience similar loading and wear patterns. The liners are attached to the tray surfaces as sacrificial components. They can be large rigid components spanning the tray or they can be assembled from multiple rigid components. These are custom-made to fit a tray of specific shape (or a specific bucket shape) and have to be stored and shipped to the site in a dedicated truck adding to the expense. In addition, dedicated attachment systems are often required to retain the wear surface in the tray of the dump truck.
The most effective materials for wear surfaces are hard materials such as cast white iron. White iron can be cast to a variety of shapes and is very wear resistant. Hard materials such as white iron are difficult to weld as the welding process degrades material properties and promotes cracking. Such wear members typically need to be attached by other non-welding means. A base of a softer metal such as steel is welded on the equipment and then the white iron wear member is secured to the steel base. The steel base is more easily worn than the wear member, but the wear member protects the base, limiting erosion and extending the life of the base.
The cast wear member can be mechanically attached to the base with a lock or other mechanical retention means requiring additional components or more complex castings. The wear members are of a size to be handled and mounted to the base relatively easily. But a large surface can require a large number of wear members to cover the surface that again require time and expense for initially installing the bases and then for replacing each of the multiple wear members to and from the bases. Each of these solutions requires extensive equipment downtime and maintenance man-hours for installation and renewal.